Abstract

The use of multicore optical fibers is emerging as a key solution to implement space-division multiplexing, essential for overcoming the capacity limits of conventional single-mode fibers. However, next-generation high-capacity optical networks will require new devices compatible with these fibers. In this work, we present an all-fiber architecture for a high-speed core-selective switch, crucial for efficient signal distribution in multicore networks. The device leverages multicore interference to achieve rapid core-switching within 0.7 ?s-three orders of magnitude faster than state-of-the-art micro-electromechanical system switches. It also maintains an average inter-core crosstalk below ?18 dB, ensuring compatibility with diverse network tasks. We validated the device’s functionality by routing optical signals ranging from 1 to 600 Gbps and successfully switching signals over a field-installed multicore fiber network. These results demonstrate, for the first time, a multicore optical fiber switch operating under real-world conditions with speeds far surpassing existing commercial devices. Potentially compatible with standard multiplexing techniques, this switch represents a significant advancement in enabling high-capacity multicore telecommunication networks. Its performance and adaptability position it as a key technology for the development of next-generation optical communication systems. © The Author(s) 2025.